Floorboard and method for manufacturing thereof

ABSTRACT

Floorboards with a surface of flexible fibers for laying a mechanically joined floating floor, and methods for manufacturing and profloorings containing such floorboards.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of Swedish Patent ApplicationNo. SE 0300479-3, filed in Sweden on Feb. 24, 2003, and U.S. ProvisionalApplication No. 60/456,957, filed in the United States on Mar. 25, 2003.The contents of SE 0300479-3 and U.S. 60/456,957 are incorporated hereinby reference.

BACKGROUND OF INVENTION

1. Technical Field

The invention relates generally to the technical field of floorboards.The invention concerns floorboards with a sound-absorbing surface offibers which can be joined mechanically in different patterns. Theinvention also concerns methods for manufacturing such floorboards. Theinvention is particularly suited for use in floating floors.

2. Field of Application

The present invention is particularly suited for use in floating floorswith mechanical joint systems. Such floors often consist of a surfacelayer of laminate or wood, a core and a balancing layer and are formedas recfloorboards intended to be joined mechanically, i.e. without glue,along both long sides and short sides in the vertical and horizontaldirection.

The following description of prior-art technique, problems of knownsystems, as well as the object and features of the invention willtherefore as non-limiting examples be aimed mainly at this field ofapplication. However, it should be emphasized that the invention can beused in optional floorboards which have a surface layer and a core. Theinvention may thus also be applicable to floors that are nailed or gluedto a base.

BACKGROUND OF THE INVENTION

Floating floors with mechanical joint systems and with a surface oflaminate or wood have in recent years taken large shares of the marketfrom, for instance, carpets and plastic flooring but also from woodenflooring that is glued to the base. One reason is that these floors canbe laid quickly and easily on a subfloor that does not have to beperfectly smooth or flat. They can move freely from the subfloor.Shrinkage and swelling occur under the baseboards and the joints betweenthe floorboards are tight. A floating floor with a mechanical jointsystem can easily be taken up and laid once more. Individual floorboardscan be replaced, the subfloor is accessible for renovation and theentire floor can be moved to a different room.

Plastic floors and textile floor coverings that are glued to thesubfloor require a perfectly flat subfloor. Laying is complicated andthe flooring cannot be removed without being damaged. Such floorings areadvantageous since they can be supplied in widths of for instance 4 m.There are few joints. Plastic floorings are impermeable to water, andboth plastic flooring and textile flooring are soft and produce a lowersound level than laminates and wooden floors.

Thus, floating floors have many advantages over floors that are glued tothe subfloor. A great drawback of such floating floors with a hardsurface of wood or laminate is, however, that they produce a high soundlevel with people walking on the floor. The sound level can be annoyingespecially in public places, such as offices, hotels and businesspremises where there are many people walking around. It would bepossible to use floating floors to a greater extent if the sound levelcould be reduced.

Definition of Some Terms

In the following text, the visible surface of the installed floorboardis called “front side”, while the opposite side of the floorboard,facing the subfloor, is called “rear side”. The sheet-shaped startingmaterial that is used in manufacture is called “core”. When the core iscoated with a surface layer closest to the front side and preferablyalso a balancing layer closest to the rear side, it forms asemi-manufacture which is called “floor panel” or “floor element” in thecase where the semi-manufacture, in a subsequent operation, is dividedinto a plurality of floor panels mentioned above. When the floor panelsare machined along their edges so as to obtain their final shape withthe joint system, they are called “floorboards”. By “surface layers” aremeant all layers applied to the core closest to the front side andcovering preferably the entire front side of the floorboard. By“decorative surface layer” is meant a layer which is essentiallyintended to give the floor its decorative appearance. “Wear layer”relates to a layer which is mainly adapted to improve the durability ofthe front side. By “laminate flooring” is meant flooring that isavailable on the market under this designation. The wear layer of thelaminate flooring consists as a rule of a transparent sheet of paperwhich is impregnated with melamine resin, with aluminum oxide added. Thedecorative layer consists of a melamine impregnated decorative sheet ofpaper. The core is as a rule a wood-fiber-based sheet. By “HDF” is meantsheet material that is known on the market under the designation highdensity fiberboard, HDF, consisting of ground wood fibers joined by abinder. When a HDF sheet is manufactured with a lower density, it iscalled MDF (Medium Density Fiberboard).

The outer parts of the floorboard at the edge of the floorboard betweenthe front side and the rear side are called “joint edge”. As a rule, thejoint edge has several “joint surfaces” which can be vertical,horizontal, angled, rounded, beveled etc. These joint surfaces exist ondifferent materials, for instance laminate, fiberwood, plastic, metal(especially aluminum) or sealing material. By “joint” or “lockingsystem” are meant coacting connecting means which connect thefloorboards vertically and/or horizontally. By “mechanical lockingsystem” is meant that joining can take place without glue horizontallyparallel to the surface and vertically perpendicular to the surface.Mechanical joint systems can in many cases also be joined by means ofglue. By “floating floor” is meant flooring with floorboards which areonly joined with their respective joint edges and thus not glued to thesubfloor. In case of movement due to moisture, the joint remains tight.Movement due to moisture takes place in the outer areas of the flooralong the walls hidden under the baseboards. By “textile floor” is meanta soft flooring which consists of oil-based synthetic fibers or naturalfibers joined to form a carpet or felt. The flooring is usually producedin a width of about 4 m and a length that can be several hundred meters.The flooring is delivered from the factory usually in rolls and isusually installed by gluing to a subfloor. By “needle felt” is meant afiber-based felt which is sold on the market under the designationneedle felt carpet. This floor consists of oil-based fibers of e.g.polypropylene (PP), nylon (PA) or polyester (PES) which are joined toform a felt. Joining takes place by a fiber mat being punched by meansof hooked needles. The rear side is usually coated with foam which mayconsist of latex and chalk.

Prior-Art Technique and Problems Thereof

To facilitate the understanding and the description of the presentinvention as well as the knowledge of the problems behind the invention,a description of prior-art technique now follows. Floorboards which inthe following are referred to as rectangular with long sides and shortsides can also be square.

Hard floorings with a surface of laminate or wood cause a high soundlevel. The high sound level arises mainly as people walk on the hardlaminate or wood surface. The sound that is produced at the surfacecauses a high sound level in the room. The sound also penetrates thefloor and into the beams and joists. To solve this problem, floatingfloors have been installed on a base of cardboard, felt, foam or likematerials. The reduction of sound thus occurs on the rear side of thefloorboard by means of special underlay materials that are appliedbetween the floating flooring and the subfloor. This can cause aconsiderable dampening of the sound level between two floor levels. Thereduction of sound that can be achieved in the room is of a limitedextent.

Another method of reducing the sound level is to glue the floorboards tothe subfloor. This results in a certain reduction of sound in the room,and the sound frequency is felt to be more pleasant. The costs are highand the laying quality is poor, with many and large joint gaps. A thirdmethod is to provide the surface of the floorboard with a surface layerof e.g. cork. This mateis softer than wood and laminate and reduces thesound level. A cork floor, however, suffers from a number of drawbacks.Durability and impression strength are relatively low, cost is high andsound reduction may be insufficient.

SUMMARY OF INVENTION

An object of the present invention is to provide floorboards which canbe joined mechanically to form a floating flooring with a low soundlevel. Such a flooring should at the same time have an attractiveappearance and allow manufacture with great accuracy.

The invention is based on a first understanding that a low sound levelshould above all be provided using a surface layer which does notproduce a high sound level when being hit with hard materials on itssurface.

The invention is based on a second understanding that floorboards with asoft surface layer having a low density have a lower sound level thanfloorboards with surface layers that are hard and have a high density.

The invention is based on a third understanding that it is possible toprovide a surface layer at a low cost, which is sound absorbing and hashigh durability and impact strength. Such a surface layer should consistof fibers that are flexible and which can be compressed when the flooris subjected to a load, for instance with people walking on its surface.These fibers can be made of materials having a relatively high densityand being very strong, for instance synthetic fibers or natural fiberssuch as wool. When the fibers are thin and joined to form a felt or acarpet with air between the flexible fibers, a surface layer is producedwhich is soft and has low density. The thickness of the fibers may be,for instance, 0.05-0.10 mm. The volume density of the surface layer canbe below 400 kg/m³, and it can preferably have a density of 150-300kg/m². This is considerably lower than wood, laminate and cork and thesound level is significantly lower than for all these materials.

The invention is based on a fourth and highly surprising understandingthat a fiber-based surface layer with low density, for instance in theform of a needle felt mat, can be applied by, for instance, gluing to acore of e.g. fiberboard. The core can be, for instance, a particleboard, MDF or HDF. This floor element can, for instance, by sawing bedivided into floor panels which are machined using, for instance, acombination of rotary knives and diamond tools so that they formfloorboards in a floating floor. The upper joint edges can be formed insuch a manner that, at the surface, they consist mainly of free fibersand closest to the core, fibers joined to the core. The surface layercan then be manufactured with great accuracy and without loose fibers.The fibers closest to the core can be joined by mixing with a flexiblematerial, such as latex. This gives the surface layer better stabilityand facilitates cleaning since dirt cannot penetrate into the lowerparts of the surface layer. Thin surface layer will be easier to handleif they are integrated with a core.

The invention is based on a fifth understanding that these floorboardscan be joined by means of a mechanical joint system which on the onehand positions the floorboards with great accuracy relative to eachother and which at the same time holds upper joint edges in closecontact. The joints between the floorboards will be very tight and theycan be made essentially invisible to the eye.

The invention is based on a sixth understanding that a floating floorwith a fiber surface can be installed quickly and rationally and at acost that does not have to exceed the cost of putty-coating of subfloorsand gluing and cutting of a textile floor covering. Attractive patternscan be provided, for instance, by floorboards with different formats anddifferent colors of the surface layer being joined to each other with anexact fit. Attractive patterns can be created, for instance with asurface of needle felt which normally does not allow very greatvariation in pattern. Thin fiber layers, for instance 1-2 mm, which areintegrated with a smooth core, can provide a perfectly smooth floor. Forinstance, when a needle felt carpet is glued to a fiberboard, thesurface will be highly stable as to shape. This facilitates, forexample, printing of advanced patterns on the fiber surface. Durabilityincreases if the surface is flat without rises.

The invention is based on a seventh understanding that a floating floorwith a sound-absorbing fiber surface and a mechanical joint system iseasy to take up. Such a floor is particularly convenient for temporaryexhibitions, business premises and the like, in which the floor ischanged frequently, and in premises subjected to great wear. Floorboardsin connection with, for example, entrance portions, in which wear andsoiling is great, can easily be exchanged.

Finally, the invention is based on an eighth understanding that floorswith different surface layers can be provided with mechanical jointsystems so as to be joinable to each other. In this way, combinationfloors can be provided which, for instance, consist of laminate floorand needle felt floor. If the floorboards have a similar thickness, thefloor will be smooth. In walking areas, such a floor can have a surfaceof needle felt in order to dampen the sound level. The other surfacesmay consist of, for instance, floorboards with a surface of laminate,linoleum, wood or plastic. These surfaces are easy to clean, andsuitable combinations of materials can provide an attractive design.

The above thus means that according to the invention it is possible toprovide a floor having all the advantages of a floating laminate orwooden floor while at the same time one of the major drawbacks can beeliminated by means of a surface layer of fibers that does not generatea high sound level.

This object is achieved wholly or partly by floorboards and a method formanufacturing that are evident from the independent claims. Thedependent claims define particularly preferred embodiments of theinvention.

According to a first aspect, in one embodiment, the present inventioncomprises rectangular or square floorboards for making a floatingflooring, which floorboards are mechanically lockable and which alongtheir edge portions have pairs of opposing connecting means for lockingof adjoining floorboards to each other both vertically and horizontally(D1 and D2 respectively), wherein the surface layer of the floorboardsconsists of flexible and resilient fibers.

In this context, the term “consists of” should be interpreted as“consisting substantially of”, taking into account that the surfacelayer, in addition to the fibers, may also comprise e.g. fiber binders,backing layers, fiber treatment agents (for repelling dirt, flameretardants etc.) or matter resulting from printing of the surface.

According to a preferred embodiment of this first aspect, thefloorboards can be provided with a surface layer which consists ofneedle felt with a density below 400 kg/m³.

Several variants of the invention are feasible. The floorboards can beprovided with any prior-art mechanical joint system. Examples ofprior-art mechanical joint systems are provided in WO94/26999,WO97/47834, WO99/66151, WO99/66152, FR-2WO02/055809, WO02/055810 and WO03/083234. Such floorboards can be laid by different combinations ofangling, horizontal snapping-in, vertical snapping-in, or folding andinsertion along the joint edge. The floorboards can also havemirror-inverted joint systems that allow joining of long side to shortside or optional sides if the boards are square.

According to a second aspect, in one embodiment, the present inventioncomprises a method for rational manufacture of floorboards as describedabove. According to this method, a surface layer consisting of flexiblefibers are joined to a core in order to form a floor element. Joiningcan occur, for example, by gluing, and the core may consist of awood-fiber-based material such as HDF, MDF, particle board, plywood etc.This floor element is then sawn up and machined to a floorboard using arotary tool. This means that the manufacturing technique ischaracterized in that the surface layer is formed by machining inconnection with the finishing of the joint edges of the floor panel.

The embodiments of the invention will now be described in more detailwith reference to the accompanying schematic drawings which by way ofexample illustrate currently preferred embodiments of the inventionaccording to its various aspects.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1 a-d illustrate manufacture of a floorboard according to anembodiment of the invention.

FIGS. 2 a-d show examples of mechanical joint systems which can be usedin embodiments of the invention.

FIGS. 3 a-c show an embodiment of the invention.

FIGS. 4 a-f illustrate the manufacture of the joint edge portionaccording to an embodiment of the invention.

FIGS. 5 a-c show a flow consisting of floorboards with different surfacelayers according to an embodiment of the invention.

FIGS. 6 a-d show embodiments of floors according to the invention.

FIGS. 7 a-e show embodiments off floors and locking systems according tothe invention.

DETAILED DESCRIPTION

FIGS. 1 a-d illustrate the manufacture of a floorboard according to anembodiment of the invention. A layer 31, which in this embodimentconsists of needle felt, is joined, for instance, by gluing to a core30. This core may consist of, for example, particle board, fiberboard,such as MDF, HDF, plywood or the like. A lower layer, for instance abalancing layer 32, can be applied to the rear side to prevent cupping.This rear layer can also be a soft material, such as foam, needle felt,cardboard or the like, which levels irregularities in the subfloor andwhich improves the reduction of sound. This lower layer is in someapplications not necessary. The floor element 3, which may have athickness of e.g. 5-20 mm, is then divided into a plurality of floorpanels 2. These panels are then machined and joint edge portions areformed so as to constitute a mechanical joint system 7, 7′. An exampleof such a joint system on the long sides 4 a and 4 b is shown in FIG. 1d. The floorboards could be produced in several alternative ways. Forexample the surface layer 31 and/or the balancing layer 32 could beapplied on the core of the floorpanels and not on the core of the floorelements.

FIGS. 2 a-d show examples of mechanical joint systems which can be usedin the invention. The joint system according to FIG. 2 a can be joinedby vertical snapping-in. In the joint system according to FIGS. 2 b and2 c, a groove 36 and a tongue 38 form the vertical joint D1. A strip 6,a locking element 8 and a locking groove 14 form the horizontal jointD2. These locking systems can be joined by angling and horizontalsnapping-in. If upper joint edges 41, 42 are compressible, the jointsystem in FIG. 2 c can be locked by vertical snapping-in. If the tongue32 is removed, the locking could be accomplished with vertical foldingwithout any snapping. A surface layer 31, which consists of e.g. needlefelt, can be pressed together, and this facilitates verticalsnapping-in. FIG. 2 d shows a different embodiment which can be joinedby angling and snapping-in. Upper joint edges 41, 42 have in thisembodiment a beveled portion.

In one embodiment, the floorboard, on a first pair of opposing jointedges, is provided with a mechanical locking system adapted for lockingthe floorboard to an adjoining floorboard both vertically D1 andhorizontally D2. This first pair of opposing joint edges may be thefloorboard's long edges. A second pair of opposing joint edges may beprovided with a mechanical locking adapted for locking the floorboard toan adjoining floorboard vertically and/or horizontally. This second pairof opposing joint edges may be the floorboard's short edges.

In one embodiment, the second pair of opposing joint edges are providedwith a mechanical locking system which only provides locking in thevertical direction, such as is the case with a prior-arttongue-and-groove system.

In another embodiment, the second pair of opposing joint edges areprovided with a mechanical locking system which only provides locking inthe horizontal direction, such as would be the case if the tongue 38 ofany one of the embodiments of FIGS. 2 b or 2 c was to be removed, whileleaving the locking strip 6 with its locking element 8 and the lockinggroove 14. In FIG. 2 d such a case would be accomplished if the tongue38 or the lower lip 39 will be removed.

FIGS. 3 a-c illustrate a floorboard which in this embodiment has a core30 of a relatively soft material, such as MDF or particle board. Thelocking system has been adjusted to the soft core by the locking element8 having a horizontal extent which is about 0.5 times the thickness ofthe core 30. The surface layer 31 has outer joint edges 40, 41 which inthis embodiment project beyond the outer parts of the core 30. Thisprojection can be some tenths of a millimeter. The outer parts of thesurface layer are pressed together in connection with laying, and thefloorboards will have very tight joints. The mechanical locking systemguides the floorboards in exact positions and ensures a high quality oflaying. In one embodiment the locking system may have a geometry where aplay may exist, between the locking surface 9 of the locking element 8and the locking groove 14, when the floorboards 1 and 1′ are pressedtogether. The core 31 can have a thickness of e.g. 6-7 mm, and thesurface layer 31 can have a thickness of 1-2 mm. In this embodiment, thetotal thickness of the floorboard can thus be about 7-9 mm, and thefloor can then be joined to ordinary laminate floors having a thicknessof about 7-8 mm. Other thicknesses can also be used in this invention.

FIGS. 4 a-4 f illustrate how joint edge portions can be machined. Wehave discovered that a soft surface layer of fibers cannot be machinedaccurately by means of cutting rotary tools which are normally used inmanufacture of laminates and wooden floors and the wood-based corematerials that are the most common ones in these cases. Loose fibers,especially in corner portions, cause a frayed joint edge. Plastics thatare used in manufacture of synthetic fibers have as a rule a meltingpoint round 120-160 degrees C. The fibers melt at high machining speeds.These problems can be solved by the surface layer being cut using, forinstance, knives. These knives TP1A and TP1B can be rotary. The angle ofaction of the knives is indicated by the arrows R1 a and R1 b in FIGS. 4a, 4 b. The knives, which can have other angles than the 90 degrees asshown, cut against the core 30, and in this embodiment the cut is placedoutside the upper and outer part of the core in the completedfloorboard. FIGS. 4 a-f show that the entire joint system can be formedusing merely 4 milling tools TP2A, TP2B, TP3A and TP3B which machine thecore. The joint system in the shown embodiment is made in one piece withthe core. It is also possible to make the whole, or parts of, the jointsystem of a material other than that of the core of the floorboard. Forinstance the strip 6 can be made of aluminum or of a sheet-formed blankwhich is machined to a strip and mechanically attached to the jointedge.

FIGS. 5 a-c show floorboards with two surface layers. The floorboards 1,1′ can, for instance, have a surface layer of laminate or wood, and thefloorboards 2, 2′ can have a surface layer of e.g. needle felt,linoleum, plastic of some other suitable material. Also othercombinations of materials may be used. FIGS. 5 b and 5 c show thatjoining to outer upper parts can take place, which are essentiallypositioned in the same plane. No transition strips are required.

In an alternative design, the fibers of the surface layer 31 may extendvertically such that the floorboard having the fiber surface layerappears slightly higher than the adjacent, normal floorboard. Hence, thevertical extension of the fiber surface layer may be used to provide adesired surface structure of the flooring, e.g. in order to provide theappearance of a rug being placed on a hard floor.

FIGS. 6 a-6 d show examples of floors that can be provided according tothe invention. In FIG. 6 a, the floorboards 2, 2′ have a surface ofneedle felt. They can be square, for instance 40×40 cm. The floorboards1, 1′ can have a surface of laminate, wood, cork, linoleum, plastic etc.For example they can have a width of 10 cm and a length of 40 cm. InFIG. 6 b, the squares are offset. If the harder floorboards 1, 1′ arepositioned at a somewhat lower level than the softer floorboards, thehard floorboards will not cause a high sound level since they will, to alimited extent, be in contact with shoes generating sound. Thus, theinvention also concerns a set of floorboards with at least two differentsurface layers to provide a floor.

FIGS. 6 c and 6 d illustrate floors consisting of two differentfloorboards with surface layers of flexible fibers which differ fromeach other with respect to color, surface structure etc. In FIG. 6 c,the floorboards are joined to form a herringbone pattern. They havemirror-inverted mechanical locking systems that allow joining of longside to short side by angling and/or snapping-in. The long sides canalso be joined by angling and/or snapping-in. If the short sides of thefloorboards in FIG. 6 c have a locking system which only lockshorizontally, the whole floor could be installed with angling only.

FIG. 7 a shows a combination floor in which one floorboard 1 has aharder surface, such as laminate, wood, linoleum, plastic etc. than another floorboard 2′. One floorboar 2′ has in this embodiment a softersurface layer which is positioned higher than the harder surface layerof the other 1′ floorboard. It is preferable to position the softersurface layer on the same or higher level than the harder surface layer.The advantage is the the softer and more flexible layer protects theedges of the hard surface.

FIG. 7 b shows a floorboard with a soft fibre layer 32 on the rear sidewhich may be used as a balancing layer.

FIG. 7 c shows a locking system which only locks horizontally and FIG. 7d shows a locking system which only locks vertically.

FIG. 7 e shows a floorboard where the thickness T1 of the soft surfacelayer 31 is equal or larger than 0.5 times the thickness T2 of the core.Such a thin core gives several advantages related to production cost,transport, installation etc. It is possible to produce a mechanicallocking system by machining in a sheet material which has a thickness of3-5 mm only. Generally diamond tools are used and in order to reach thebest cost and quality levels, the tools should be as thick and compactas possible. A difficult part to produce is the groove 36. In thisembodiment the grove 36 and the tongue 38 has a vertical thickness T3which is larger or equal than 0.5 times the thickness T2 of the core 30.

It is obvious that all prior-art parquet and tile patterns can be madeby means of floorboards according to the invention. The sides of thefloorboards need not be perpendicular. The soft surface allows that alsothe thickness may be varied between different floorboards. If the coreis made of a moisture-proof material, such as plastic or compactlaminate, floorboards with a fiber surface resembling synthetic grasscan be provided. Such floorboards can be laid immediately on the groundor on concrete, and they may, for instance, constitute tees on golfcourses, balcony floors etc. During the winter, the boards can be takenup and stored under a roof.

Although only preferred embodiments are specifically illustrated anddescribed herein, it will be appreciated that many modifications andvariations of the present invention are possible in light of the aboveteachings and within the purview of the appended claims withoutdeparting from the spirit and intended scope of the invention.

1. Floorboards comprising a surface layer and a core, for making afloating flooring, which floorboards are mechanically lockable and whichalong their edge portions have pairs of opposing connectors for lockingsimilar, adjoining floorboards to each other both vertically andhorizontally, wherein the surface layer comprises flexible resilientfibers. 2-13. (canceled)